ML25155B256

Summary of Hybrid Public Meeting- Guidance Development for Accelerated Material Qualification

ML25155B256
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Issue date:	06/09/2025
From:	Savara A NRC/RES/DE
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U.S. Nuclear Regulatory Commission Public Meeting Summary June 2, 2025

Title:

Public Meeting on Guidance Development for Accelerated Material Qualification Meeting Identifier: 20250482 Date of Meeting: May 6, 2025 Location: Hybrid, One White Flint North, 01F23 and Microsoft Teams Type of Meeting: Information Meeting with a Question and Answer Session.

Purpose of Meeting:

In response to the ADVANCE Act and as described in Table 3 of the report "Advanced Methods of Manufacturing and Construction for Nuclear Energy Projects" (ML24292A171), NRC staff are acting to potentially develop guidance on accelerated material qualification. NRC staff held a public meeting from 1 PM - 5 PM on May 6, 2025 with advanced reactor vendors and other stakeholders. The meetings focus was to hear from the technical community on activities related to accelerated material qualification via advanced manufacturing and traditional manufacturing for use in near-term and mid-term advanced reactors designs. This is part of the agencys efforts to enable efficient safety and licensing reviews.

Summary of Presentations Portion of Meeting:

Meredith Neubauer (NRC) opened the meeting, introducing herself as the facilitator. She provided an overview of the meeting logistics, participation guidelines, and the category of the meeting.

Christian Araguas (NRC) provided opening remarks which described the purpose of the meeting, with the ADVANCE Act being a driver for some significant changes at the NRC. The NRC developed an ADVANCE Act Section 401 report which included a number of different activities that the agency would consider doing. One of those topics was on developing accelerated material qualification guidance. He noted that the public meeting had a packed agenda and that NRC staff were looking forward to hearing from the participants.

The meeting then proceeded with presentations from the Department of Energy Office of Nuclear Energy (DOE-NE), the Electric Power Research Institute (EPRI), and Industry Representatives.

1. Meimei Li (DOE-NE) presented on "AMMTs Perspectives on Accelerated Material Qualification for Advanced Reactors." She outlined the DOE-NE Advanced Materials and Manufacturing Technologies (AMMT) program, which focuses on four areas: advanced materials and manufacturing, rapid qualification, environmental effects, and technology maturation. Her talk emphasized the AMMT programs perspective on accelerated material qualification, including not only development but also the long-term effects of temperature, stress, radiation, and corrosion. AMMT has been developing a rapid qualification framework that is designed to be physics-based, data-driven, and is currently primarily focused on high-temperature materials. The framework is founded on

understanding and predicting how the processing input parameters, including material composition, impact material performance in the reactor. The framework also incorporates advanced experimental methods, in-situ process monitoring, and computational tools. The program is investigating radiation effects through neutron irradiation testing and corrosion effects through corrosion studies in molten salts and liquid sodium. AMMT has technology maturation efforts which involve working with entities for component fabrication, testing, and also collaborating with others to develop new ASME code cases (e.g., for Laser Powder Bed Fusion of 316H and long-term data for Alloy 709). Within the AMMT framework, there is a deliberate effort to integrate data across the lifecycle, from design through performance. The presentation listed some opportunities that could benefit from NRC guidance, including areas such as digital-driven qualification, in-situ monitoring, non-standard specimen data, and long-term behavior predictions. The AMMT program aims to support a wide range of reactor types (from conventional to advanced, and from micro reactors to large reactors) to shorten the timelines of and reduce the costs of technology development, for the benefit of the broader community.

2. Marc Albert and Chris Wax (EPRI) presented on "Accelerating the Deployment of Materials and Advanced Manufacturing Methods for Nuclear Applications." They emphasized that Code qualification alone doesnt mean a material is approved for Nuclear Service. ASME Code coverage for new alloys can take a decade, and gaps remain in experimental data, infrastructure, and regulatory guidance. EPRI has a project on accelerated qualification which has issued EPRI Report 3002029265, Accelerating the Qualification of Structural Materials for Advanced Reactors. The report examined the advantages and disadvantages as well as knowledge gaps for various accelerated qualification methods, and a follow up step for EPRI is to look at how to include those methods into a qualification framework. EPRI is using both existing data and experiments to create accelerated qualification examples. For example, using extensive database records of wrought 316H weld metal creep rupture data coupled with the data on some limited 316H GMA-DED builds, being able to package that data together and bring that forward to establish code coverage within ASME Section III Division 5. The presentation noted that ASME Section III Division 5 does not cover environmental effects, and that NRCs Interim Staff Guidance (DANU-ISG-2023-01) does not stipulate specific methods for evaluating deterioration as result of corrosion and service. The presentation noted that during the operational phase, various methodologies such as in-service inspection, monitoring, and/or surveillance may be used to assess degradation (some are currently covered under ASME Section XI Division 2). EPRI identified collaboration with DOE and industry, and particularly large-scale demonstrations, as key to accelerating deployment.

3. Zefeng Yu (Westinghouse) presented on "Material Qualification for the eVinci Microreactor," a 15 MWt reactor using a graphite block core. Westinghouse's qualification strategy begins with ASME Code and NRC guidance, turning to existing data and testing for non-Code covered materials. He highlighted key challenges for metallic material qualification including 1) a lack of direction for addressing environmental effects (e.g., irradiation, oxidation, etc.), which is not explicitly addressed

in ASME Section III Div. 5, and 2) the lengthy testing needed to qualify new materials, even with extrapolated creep data for long-term high temperature testing. To address some of these considerations Westinghouse conducts internal efforts to create Phenomena Identification and Ranking Tables. The presenter relayed that Westinghouse asks that the NRC endorse ASME Section III Div. 5 HBB-Y for material qualification, which Westinghouse is currently generically following. The speaker noted that an NRC endorsement could enable materials to be deployed without the time delay of adding materials into the Codes. He then spoke about how graphite qualification is challenged by limited Code-approved grades and irradiated material properties data, such that Westinghouse is using statistical methods, interpolation, and extrapolation to fill data gaps. The presenter relayed that Westinghouse asks that NRC show that the models included in TLR-RES/DE/REB-2022-1 apply to grades of graphite other than IG-110, and publish the corresponding material properties and parameterizations, so that these models can be used for other grades. He then conveyed that Westinghouse is conducting Heat Pipe Testing, Material Compatibility Testing, and Graphite Testing involving gathering high temperature data, including time-dependent data. He noted that Westinghouse is participating in pre-application engagements with NRC and submitting white papers, including on Composite Material Qualification and Testing, as well as Component Qualification, with both of those white papers already submitted to NRC.

4. Craig Gerardi (Kairos Power) spoke about "Kairos Power: An Iterative Approach for Reactor Materials." Their presentation introduced their KP-FHR reactor as a pool-type fluoride-salt cooled reactor, with a pebble bed surrounded by a graphite reflector. He noted that they have an iterative approach for reactor development, and that the materials qualification process is underway for their first reactor, Hermes 1. Hermes 1 is designed to use 316 H steel with 16-8-2 weld filler for the reactor vessels. He discussed how they are looking into Autogenous Electron Beam Welding of 316H for later reactors.

They are in the process of extending the code case for 16-8-2 filler metal to higher temperatures in ASME Code Section III Div. 5. They have completed a technical assessment for their possibility of using electron beam welding in future reactors and are communicating with the ASME Allowable Stress Committee with the potential to move on to testing. He also highlighted new materials developments, such as new alloys like 709 for improved creep resistance and Hast-N type alloys for use in fluoride salts. He noted Kairos Power is also following progress in advanced manufacturing and welding techniques, though Kairos Power is currently not actively investigating or planning to use those techniques for making any safety significant components.

5. Luke Andrew (Aalo) presented on Aalos Advanced Manufacturing and Qualification Approach for Intermediate Heat Exchangers. Aalo aims for more rapid nuclear reactor manufacturing and deployment. Their design involves a printed circuit heat exchanger (PCHE), which requires 80% less space and will be produced using an advanced manufacturing method called diffusion bonding. Both the material that they plan to use, 316L and the manufacturing method of diffusion bonding, are not yet covered under ASME Section III, though are partially covered in other sections. Aalo is in the process of trying to get ASME Section III Code coverage for this material and this production process combination. Aalo is also building a test facility to support Code coverage

applications and NRC licensing applications. Aalo is currently planning to complete testing of various reactor systems, followed by creating a DOE site test reactor, which would then be followed by creating commercialized reactors.

6. Bridgette Hannifin (TerraPower) presented on Metallic Materials Development for the NATRIUM Advanced Reactor. She noted TerraPower is planning beyond demonstration reactors and evaluating technologies that may benefit commercialization of reactors. Challenges with ASME Section III Div. 5 were highlighted, including issues with fatigue test HBB-2800, which isnt suitable for the thinner components (such as certain plates and pipes) used in Natriums lower-pressure design. She discussed how TerraPower is conducting environmental effects testing on materials, including both sodium interactions testing and irradiation testing, utilizing in-situ experiments. Lastly, she summarized the overall challenges they face such as long qualification time relative to construction time, lack of specification for how to address full environmental effects relevant to time-temperature properties, and how in-service inspection and in-situ testing is more challenging in pool type reactors, leading to increased consideration of monitoring technologies.

7. Parker Buntin (Radiant Nuclear) presented on Qualification of Metallic Materials for Kaleidos. He outlined that a qualified material should have a strong technical basis to meet design life requirements. He introduced Radiant Nuclears qualification process as having three paths: 1) materials with no gaps for justifying the technical and qualification basis just requiring documentation for qualification, 2) materials with sufficient existing third-party data for technical and qualification basis, and 3) materials with data gaps requiring new testing for technical and qualification basis. Three examples were provided, one for each path: 316H austenitic stainless steel, A286 bolting material, and an A625 Ni superalloy. He provided some thoughts on how to accelerate qualification, such as by using standardized materials covered by other (non-nuclear) Codes, the possibility of bullk-accepting properties from existing credible databases (such as from international partners), and subjecting first of their kind technologies to increased surveillance and performance monitoring.

Some key points expressed during the presentations by industrial representatives were thus: (1)

A request for NRC to endorse following HBB-Y as an acceptable approach for vendors to qualify and deploy materials faster, without needing to have materials added into the Codes (2) A request for NRC to provide guidance on advanced manufacturing qualification expectations, with vendors not providing any specific emphasis on modeling and simulation, (3) Vendors do plan to do in-situ surveillance and/or condition monitoring.

Summary of Discussion Portion of Meeting:

Raj Iyengar moderated the discussion session during the meeting. Selected highlights from the discussion were:

1. Some materials under consideration for use by industry are currently covered by various Codes, but not by ASME Section III Div. 5 for high temperature reactors.

2. The ASME Code does not include rules for environmental factors for Code covered materials which is a challenge for designing towards regulatory approval.

3. Establishing long-term performance of materials in irradiated environments is currently a challenge, both due to lack of neutron irradiation testing facilities available and also due to the amount of time that long-term tests take.

4. A Westinghouse representative expressed that NRC endorsement of ASME Code,Section III, Division 5, Nonmandatory Appendix HBB-Y, would help to de-risk development of new materials not included in ASME Code.

5. Modeling and simulation can potentially bridge gaps in data. AI/ML may be possible to use in conjunction with physics-based models.

6. Inconel 625 (UNS N06625) has the potential to be used for a new ASME code case to demonstrate a shortened timeline for adding Code coverage of a new material. Alloy 625 has a large amount of data available that has been generated by national laboratories and industry and could potentially be put together for a community Code Case.

7. Batch qualification of materials and/or establishing equivalency based on data from other industries may allow industry to shorten timelines from design to application and use.

8. Industry considers the regulatory risk for using new materials that are not already covered by ASME Code when selecting materials.

Greg Oberson (NRC) delivered closing remarks, thanking all participants for engaging in the public meeting.

Meredith Neubeuer (NRC) adjourned the meeting, noting that members of the public can also ask questions outside of the meeting, by contacting the appropriate NRC contact, and by using the NRC Public Meeting Feedback form at feedback.nrc.gov and meeting code 20250482.

Related Documents ML25121A278 - 05/06/2025 Public Meeting on Guidance Development for Accelerated Material Qualification.

ML25129A088 - 05/09/2025 Public Meeting Presentations - Accelerated Material Qualification ML25135A064 - 05/09/2025 Public Meeting Transcript - Accelerated Material Qualification Attendees:

Full Name Affiliation Marc Albert EPRI Christian Araguas NRC Egemen Aras Aalo Ibrahim Attieh Aalo Meg Audrain NRC Christopher M Barr DOE Jackson Barth NRC

Joseph Bass NRC Ryann Bass NRC Jeremiah Beam DOE Jana Bergman Curtiss-Wright Andrew Bowman Westinghouse Jack Minzer Bryant NRC Angie Buford NRC Parker Buntin Radiant Nuclear Evan Ray Bures Aalo Rob Burg EPM, Inc Mat Burton NRC David C.

Radiant Nuclear Dallin John Carter Aalo Dirk Cairns-Gallimore DOE Partha Chandran Aalo Robert Davis NRC Candace de Messieres NRC David Dijamco NRC Daniel Eisen Westinghouse Jon Facemire NEI Carolyn Fairbanks NRC Chris Fanning Radiant Nuclear Asmaa Farag Aalo Lucieann Vechioli Feliciano NRC Kade Fish Aalo Eric Focht NRC Kyle Francis Aalo Craig Gerardi Kairos Kerwin Gonzalez Aalo Bruce Greer EPRI Michael Hahn Aalo Bridgette Hannifin TerraPower Matt Hansink Aalo Trey Hathaway NRC Emma Haywood NRC Matthew Hiser NRC Amy Hull NRC Raj Iyengar NRC Joel Jenkins NRC Jeff Jones Aalo Meimei Li ANL Bruce Lin NRC Luke Andrew Aalo

Curtis Lurvey NRC John Matrachisia NRC Tyrell Mauseth Aalo Julianne McCallum NEI Michael D. McMurtrey INL Mike Melton Unknown Hector Mendoza NRC Carol Moyer NRC Ewa Muzikova Unknown Mark Nefzger Aalo Christopher Nellis NRC Meredith Neubauer NRC Ingrid Nordby Deep Fission Greg Oberson NRC Hakan Ozaltun NRC Eric Palmer NRC Cory Parker NRC J Price Kairos Steven Pope Islinc Kathleen Nelson Romans Aalo Dave Rudland NRC Steve Ruffin NRC Aditya 'Ashi' Savara NRC Gabrielle Schreier GE Ting-Leung Sham NRC Curtis Smith MIT Amanda J Spalding Westinghouse Forrest Thompson Aalo Jason Tokey NRC Spencer Toohill Unknown Christopher Ulmer NRC Vince Voltaggio NRC Hayley Wagreich Westinghouse Yanli Wang ORNL Chris Wax EPRI Gregory Wildes Aalo Richard Williams Aalo John Wise NRC Jasper Wittig Neal R Gross Chanson Yang Radiant Nuclear Zefeng Yu Westinghouse